Swine flu's spread

The spread of the infection in Germany wasn't surprising since many people have been returning from vacation spots, including Spain, where they are thought to have caught the virus, Joerg Hofmann of the Institute of Virology at the Charite - Universitaetsmedizin Berlin told Deutsche Welle.

Germany's infectious disease center, the Robert Koch Institute, said there were 3,810 confirmed cases of swine flu, also called A (H1N1) on Monday. That marks an increase of 461 cases in three days.

Deutsche Welle: Is the swine flu becoming more dangerous in Germany? Is it time for Germans to get nervous?

Joerg Hofmann: No one needs to get nervous. We have expected an increase in suspected cases as well as infected people, especially when people return from vacation from endemic areas from the virus is circulating.

There have been a lot of cases in Germany and nearly all are proving to be mild. Can you explain why that's the case?

The main reason is the properties of the virus itself. When a virus wants to replicate, it has to infect a host cell, and the outcome of this infection depends mostly on the properties of the virus itself. That would mean in this case that the virus is not that virulent in the host - a spread of the viral infection in the body is limited, so that is why people are not getting seriously sick.

Germany has an ageing population, but the virus affects mainly young people. Shouldn't the number of cases be somewhat limited in relation to the population?

It should be, but what we see in fact is that Germany has the second highest level of infected people in Europe after Great Britain, so there seems to be no correlation between the mean age of the population and virus distribution.

Also, experts aren't sure why younger people are more affected, but they suspect that older people may still have some immunity toward a virus that may circulated 20 or 30 years ago. So they are possibly benefitting from this immunity which younger people may not have. But hat is all speculation - nothing is certain yet.

There was talk of possible mutation of the virus ahead of the northern hemisphere's winter and the increase of influenza cases. Is that still a serious concern?

That's always a concern. With the influenza viruses, which are known to be quite variable and change their genetic material and viral proteins, we expect a change in structure and the relation of the virus to the host cells, but we cannot predict anything about how the virus will be in late wintertime. That is why we need a new influenza vaccine each year, because the virus mutates.

In this case, some changes will happen, but we cannot predict them. That's why we can't say whether the virus will become a killer virus.

But the risk is potentially there?

Yes, it's there, but it's year every year, not just in 2009.

How effective would a vaccine now being developed be at protecting people this winter?

Experts look at the structure of the virus currently circulating. Once it's clear what its structure is, then vaccines are manufactured that contain these properties.

Basically, we have more than one vaccine available. At present, we have access to eight different vaccines produced in various ways. All of these vaccines should be available by September or October, and we expect that these vaccines will be helpful in fighting off the virus. But, you have to administer two doses (an influenza shot is usually just one dose), and in addition a vaccine exists for the seasonal virus. So there are two shots for the pandemic virus and one for the seasonal, making a total of three.

So, you believe that could cover possible dangers even if mutations occur?

Yes, that's what experts expect and predict.

Ahead of winter, however, the rest of Germany's states will end their summer vacation at the end of August. Places where holidays are already coming to a close have seen the increase in swine flue cases. Do you expect another jump in cases across Germany at the end of August?

We expect a continual increase of suspected and actual cases of infected people at the end of summer when people return from vacations.

Do you have any advice for people who are worried?

People shouldn't panic! People should take every precaution they can with personal hygiene, like washing their hands frequently, coughing and sneezing into their shirtsleeves rather than into their hands or out into the open air. But, people still shouldn't panic about the virus.

Interview: Louisa Schaefer

Editor: Sean Sinico